test(mysql): enhance datatype tests with JSON/Binary/Decimal/Datetime/Enum/Set/Geometry

Add 28 comprehensive datatype tests to mysql_z_unit_feature_raw_type_test.go:

JSON (8 tests):
- Insert, Extract (JSON_EXTRACT), Set (JSON_SET), Array operations
- NULL handling, Complex nested JSON, Query with WHERE, Update

Binary (4 tests):
- Small binary data, Large 1MB+ binary with integrity check
- Empty and NULL binary values

Decimal (4 tests):
- High precision (65,30), Arithmetic calculation
- Boundary values (max/min/zero), NULL handling

Datetime (5 tests):
- Timezone handling, Microsecond precision (DATETIME(6))
- Boundary values (1000-01-01 to 9999-12-31)
- NULL handling, Update operations

ENUM (2 tests):
- Valid values insertion and verification
- Invalid value rejection (strict mode)

SET (2 tests):
- Valid single/multiple values
- Empty SET values

Geometry (3 tests):
- POINT type with ST_GeomFromText/ST_AsText
- POLYGON type operations
- NULL handling

ref gogf#4689

Author: lingcoder